On the Performance of Hybrid Natural Rubber Rubberized Concrete

摘要

Waste rubber is an environmental concern. The large global market of concrete products could usefully consume this waste, even if the fractions used were very low, provided such concrete mix had sufficient strength and other characteristics. Therefore, the properties of concrete mixes that include natural rubber were studied at 28 days of age, which is a standard time to characterize hardened concrete properties. We included two types of natural rubber in this study, namely natural rubber latex (NRL) and discarded rubber glove. First, 60% concentrate latex (HA: high ammonia) was used in latex per cement ratio 0.10 by volume. Second, discarded rubber gloves, passed through a #6 sieve with 3.36 mm size, were used to investigate effects of soft rubber particles, on strength and insulation properties of lightweight concrete. The hybrid rubberized concrete mixes had 0%, 10%, 20% and 40% partial substitution of sand by volume, at water-cement ratio of 0.45 by volume. Density, compressive strength, flexural strength, insulation property, and coefficient of thermal conductivity were measured. A small 10% fraction of rubber particles improved flexural strength. However, compressive strength decreased with the amount of rubber in concrete. The thermal conductivity was slightly lower than that of normal concrete. Natural rubber addition can produce a moderately lightweight concrete, with good thermal insulation, and the inclusion of rubber glove waste in concrete aggregate appears feasible. Applications could also include non-primary structural uses with medium to low strength requirements, benefiting from other features of concrete. The results suggest that waste rubber can be used to create value-added concrete composites with sufficient structural strength, and improved thermal insulation.